1. Statement of the Technical Field
The inventive arrangements relate to antennas, and more particularly to methods and systems for adapting multi-band antennas for portable handheld transceivers.
2. Description of the Related Art
Multiband hand-held portable radios are rapidly becoming popular among tactical and public safety radio users. The antennas used for these multiband radios are usually flexible multi-element whip antennas. Multiple elements are required within the antenna to provide functionality on the various different frequencies at which the multi-band radio operates. For example, at least three separate antenna elements can be used to operate the antenna on the VHF, UHF, and 700/800 MHz bands. Although such antennas work reasonably well, they are often relatively large, to accommodate the wide range of frequencies employed. In fact, users who are experienced with single-band radios often complain the multiband antennas are too long and interfere with user mobility.
Current antenna development is focused on making antennas smaller, including plans to reduce performance in the least-used band in exchange for smaller size elements. However, smaller sized antennas almost inevitably lead to reduced performance; and the advantage of multi-band radios is diminished if performance on some bands is sacrificed merely to facilitate smaller antenna size.
Many portable radios are designed for use with an accessory item such as a speaker-microphone. The portable radio is designed to be attached to the user's belt, to accommodate the size and weight of the radio, whereas the smaller and lighter accessory item can located in a more convenient location. For example, speaker-microphones are often worn at the shoulder, where the user can more easily hear the audio they produce and communicate speech audio to the microphone. Some designers have taken advantage of the speaker-microphone by mounting on it a small additional antenna, usually for the 700-800 MHz band of a multi-band radio. The antenna in such designs is usually mounted directly to the housing of the speaker microphone. This arrangement improves coverage, but does not improve multiband performance. Indeed, remote antennas mounted on speaker microphones must be small because of proximity to the user's face and ears.